1. Field of the Invention
The present invention relates to digital communications signals, and more particularly, to upconversion of digital signals.
2. Background of the Invention
Cable television systems generally require a conversion system for frequency converting the transmitted channels from baseband frequencies to their designated RF frequencies for transmission over the cable medium. This system is typically part of a cable television (CATV) headend system, where the composite, multi-channel CATV signal is generated and amplified for distribution to customers.
Within existing headend systems, each frequency converters typically use multiple analog mixing stages, with one or more analog phase-locked loops (PLL) to generate the local oscillators. One converter is required for each channel, and there can be more than one hundred channels in a typical CATV system. These systems are often costly and require significant amounts of hardware. Additionally within existing systems, control of signal amplitude for each channel can be complex.
What is needed is a cost-effective system and method for frequency converting baseband television signals and creating composite, multi-channel CATV signals within a CATV headend system.